The time it takes to sharpen a sword with a whetstone can vary depending on factors such as the condition of the blade, the skill level of the person sharpening it, and the desired level of sharpness. Generally, sharpening a sword with a whetstone requires patience and attention to detail.

The process involves carefully running the whetstone along the blade at the correct angle, gradually removing any dullness or imperfections and creating a keen edge. The time required can range from several minutes to potentially hours, depending on the length of the blade and the amount of work needed.

For experienced individuals who are proficient in sword sharpening techniques, it may take less time to achieve the desired sharpness. However, for those who are less experienced or dealing with a blade that requires more significant repair or reprofiling, the process may take longer.

It's important to note that proper technique and consistent strokes are crucial in achieving an even and sharp edge while avoiding any damage to the sword. Rushing the process or applying excessive force can lead to suboptimal results or potential harm to the sword.

If you are unsure about sharpening a sword yourself, it is recommended to seek guidance from a professional or an experienced individual with expertise in sword maintenance and sharpening. They can provide proper guidance, ensure the safety of the sword, and help you achieve the desired results.